1. Field of the Invention
The present invention relates to an SOI (Silicon On Insulator) substrate having a single crystal silicon layer on one surface of a support substrate, an element substrate having the SOI substrate, a semiconductor device having the SOI substrate, an electro-optical apparatus having the element substrate, an electronic equipment, a method of manufacturing the SOI substrate, a method of manufacturing the element substrate, and a method of manufacturing the electro-optical apparatus.
2. Description of the Related Art
At first, a semiconductor technique for forming a single crystal silicon thin film on an insulation substrate and, by using the single crystal silicon thin film, forming a semiconductor device is referred to as an xe2x80x9cSOI techniquexe2x80x9d. This technique is widely used since it has the merits of a higher speed of an element, a lower consumptive electric power, a higher integration and the like.
As one of the SOI techniques, there is a technique for manufacturing the SOI substrate by laminating the single crystal silicon substrate. The method of manufacturing the SOI substrate and the structure thereof are briefly explained here with reference to FIG. 28(a) and FIG. 28(b).
At first, as shown in FIG. 28(a), a single crystal silicon substrate 1003, whose surface is oxidized to be a silicon oxide film 1002 at a lamination side thereof, is laminated on a surface of a support substrate 1001 by using a hydrogen coupling force. Then, their lamination strength is increased by a heat treatment. After that, as shown in FIG. 28(b), the thickness of the single crystal silicon substrate 1003 is reduced by grinding, polishing, etching or the like to thereby form a single crystal silicon layer 1004. Accordingly, the SOI substrate is manufactured in which the silicon oxide film 1002 and the single crystal silicon thin film 1004 are laminated in this order on the surface of the support substrate 1001.
According to the above-mentioned method of manufacturing the SOI substrate, the single crystal silicon thin film 1004 that is excellent in the crystal property can be formed as the thickness of the single crystal silicon substrate 1003 is reduced. Thus, it is possible to produce a device having a high performance.
The SOI substrate manufactured by such a laminating method is used to produce various devices, similarly to a bulk semiconductor substrate (i.e., a semiconductor integrated circuit). However, as the feature different from the bulk substrate, the SOI substrate has a feature that the substrate made of various materials can be used as the support substrate.
That is, the typical silicon substrate can be naturally used as the support substrate. Moreover, it is possible to use a transparent quartz substrate (having an optically transparent property), a glass substrate or the like. For this reason, for example, by forming the single crystal silicon thin film on the substrate having the optically transparent property, a transistor element, such as MOSFET or the like for driving a liquid crystal of a high performance can be formed by using the single crystal silicon thin film which is excellent in the crystal property, even in an apparatus requiring the optically transparent property, for example, a transparent type of a liquid crystal display device.
However, if the SOI substrate is manufactured by using the quartz substrate or the glass substrate as the support substrate, and the transistor element is formed on the surface thereof, impurities contained in the support substrate may be permeated through the silicon oxide film and diffused into the side of the transistor element. This results in the fear of the deterioration in the element property.
Also, there may be a case that the impurities such as Na+, K+, Clxe2x88x92 and the like are absorbed from the atmosphere onto the lamination plane, when the support substrate and the single crystal silicon substrate are laminated together in the process for manufacturing the SOI substrate, irrespectively of the kind of the support substrate. In this case, in the manufactured SOI substrate, the above-mentioned impurities are sandwiched between the support substrate and the silicon oxide film.
If the SOI substrate having the above-mentioned structure is used to form the transistor element on the surface, the impurities sandwiched between the support substrate and the silicon oxide film are permeated through the silicon oxide film and diffused into the transistor element side. This results in the fear of the deterioration in the element property.
When the support substrate and the single crystal silicon substrate are laminated together, a dust-proof filter or the like may be used in order to prevent the atmospheric impurities from being absorbed onto the support substrate. Actually, even if the dust-proof filter is used, it is difficult or impossible to perfectly prevent the atmospheric impurities from being absorbed onto the lamination surface.
Secondly, for example, in a case of an electro-optical apparatus of a TFT active matrix driving type, if an input light is irradiated onto a channel region of a thin film transistor (hereafter, which is referred to as a TFT (Thin Film Transistor) as the occasion demands) for a pixel switching operation, which is disposed at each pixel, an optical excitation causes an optical leak current to be generated, which changes the TFT property. In particular, in a case of an electro-optical apparatus for a light valve in a projector, since the strength of the input light is high, it is important to perform a light shield for the input light with respect to the channel region of the TFT as well as the peripheral region thereof. So, the light shield is performed with respect to the channel region as well as the peripheral region thereof by using a light shield film, which is originally designed to define an open region of each pixel and is disposed on an opposite substrate, and/or by using a data line, which is passed over the TFT on the TFT array substrate and is made of a metallic film such as Al (Aluminum) or the like.
In particular, there may be a case that the light shield film made of, for example, metal of high melting point is disposed even at a lower side of the TFT on the TFT array substrate. By disposing the light shield film at the lower side of the TFT in this manner, it is possible to prevent (i) a rear reflection light from the side of the TFT array substrate and (ii) a return light, such as a projection light which has passed through a prism or the like from another electro-optical apparatus in case of combining a plurality of electro-optical apparatuses through prisms and the like to thereby configure one optical system, from being inputted to the TFT of the electro-optical apparatus.
However, according to the research of the inventor of this application, the light shield film, which is formed at the lower side of the TFT and is made of the metal of the high melting point and the like, exhibits the tendency of the increase in aging oxidation during the manufacture of a product or the usage after the completion of the product. Then, if such oxidation is increased in the light shield film, it is confirmed that a light transmission rate is increased depending on the degree of the oxidation. This results in a problem that the increase in the oxidation causes the original function of the light shield film to be not sufficiently provided. For example, if a normal pressure oxidation at an oxygen content of 15% and a water content of 85% is performed with respect to the TFT array substrate in which the light shield film made of such high melting point metal is formed at the lower side of the TFT, the example is confirmed in which the light shield film having a film thickness of about 200 nm is perfectly oxidized even if it is covered by the protective insulation film made of silicon oxide film having a film thickness of about 800 nm.
Moreover, according to the research of the inventor of this application, the above-mentioned arrangement of the light shield film made of the high melting point metal and the like at the lower side of the channel region of the semiconductor layer constituting the TFT results in a problem of the contamination caused by the light shield film in this semiconductor layer (e.g., the contamination caused by the diffusion of the impurities and the like). That is, as compared with the case in which such a light shield film is not disposed, the example of the increase in the impurities permeated into the semiconductor layer is also confirmed, which results in a problem of the deterioration in the transistor property of the TFT.
The present invention is proposed in view of the above-mentioned circumstances. Firstly, it is therefore an object of the present invention to provide an SOI substrate, which can almost perfectly prevent impurities contained in a support substrate or impurities absorbed on a lamination plane between the support substrate and a single crystal silicon substrate from being diffused into a side of a single crystal silicon layer, and a method of manufacturing the same.
Another object of the present invention is to provide an element substrate and a semiconductor device, which can almost perfectly prevent impurities contained in a support substrate or impurities absorbed on a lamination plane between the support substrate and a single crystal silicon substrate from have an influence on a transistor element, and a method of manufacturing the same.
Still another object of the present invention is to provide an electro-optical apparatus and an electronic equipment each provided with this element substrate, which can prevent a deterioration in a property of a transistor element.
Secondly, it is therefore an object of the present invention to provide: an electro-optical apparatus, in which a light shield film is used to make a light-proof property excellent, and it is possible to reduce a drop in a light shield performance cause by an oxidization of this light shield film, and it is possible to suppress a bad influence on a semiconductor layer or the like that results from a contamination of this light shield film, and it is possible to exhibit a bright picture display at a high quality; a method of manufacturing the same; and an electronic equipment having the electro-optical apparatus.
At first, the inventor carried out the various considerations in order to solve the above-mentioned problems. As a result, it is found out that the impurities contained in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate are not permeated through the silicon nitride film or silicon nitride oxide film, and the present invention is completed by noticing this fact.
The above object of the present invention can be achieved by an SOI substrate provided with: a support substrate; a single crystal silicon layer disposed above one surface of the support substrate; an insulation portion disposed between the support substrate and the single crystal silicon layer, the insulation portion comprising a single layer of an insulation film or a lamination structure of a plurality of insulation films, and including a silicon nitride film or a silicon nitride oxide film.
According to the SOI substrate of the present invention, by employing such a structure that the insulation portion including the silicon nitride film or silicon nitride oxide film is disposed between the support substrate and the single crystal silicon substrate, the impurities contained in the support substrate cannot be permeated through this the silicon nitride film or silicon nitride oxide film. Therefore, it is possible to almost perfectly prevent the impurities contained in the support substrate from being diffused toward the single crystal silicon layer.
In one aspect of the SOI substrate of the present invention, the insulation portion comprises the lamination structure including (i) the silicon nitride film or silicon nitride oxide film and (ii) a silicon oxide film formed on a top surface or a bottom surface of the silicon nitride film or silicon nitride oxide film.
According to this aspect, by virtue of the lamination structure including (i) the silicon nitride film or silicon nitride oxide film and (ii) the silicon oxide film, it is possible to almost perfectly prevent the impurities contained in the support substrate from being diffused toward the single crystal silicon layer.
In another aspect of the SOI substrate of the present invention, the support substrate has an optically transparent property.
According to this aspect, by constituting the support substrate from a light transparent substrate such as a quartz substrate, a glass substrate or the like, it is possible to apply the SOI substrate of the present invention to a device for transmitting a light such as a liquid crystal device of a transparent type.
In another aspect of the SOI substrate of the present invention, a film thickness of the silicon nitride film or silicon nitride oxide film is 100 nm or less.
According to this aspect, it is possible to prevent the light transmission rate from being dropped due to the existence of the silicon nitride film or silicon nitride oxide film.
The above object of the present invention can be also achieved by an element substrate including a transistor element and the above described SOI substrate of the present invention, the transistor element including a semiconductor layer comprising the single crystal silicon layer.
According to the element substrate of the present invention, since it is possible to almost perfectly prevent the impurities contained in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate from being diffused toward the single crystal silicon layer. Therefore, it is possible to prevent the performance of the transistor element form being degraded.
The above object of the present invention can be also achieved by a first electro-optical apparatus provided with (A) the above described element substrate of the present invention, (B) another substrate opposed to a plane, on which the transistor element is formed, of the element substrate, and (C) an electro-optical material layer disposed between the element substrate and the another substrate.
According to the first electro-optical apparatus of the present invention, since it is provided with the above described element substrate of the present invention, it is possible to prevent the property of the transistor element from being deteriorated, and the performance thereof can be improved.
In one aspect of the first electro-optical apparatus of the present invention, a light shield film is formed on a bottom surface of the silicon nitride film or silicon nitride oxide film through an insulation film comprising a silicon oxide film.
According to this aspect, it is possible to effectively prevent the diffusion of the impurities toward the transistor element from the light shield film, which is disposed to reduce the light leak current in the transistor element, by virtue of the silicon nitride film or silicon nitride oxide film and the silicon oxide film.
The above object of the present invention can be also achieved by a first electronic equipment having the above described electro-optical apparatus of the present invention.
According to the first electronic equipment of the present invention, since it is provided with the above mentioned first electro-optical apparatus of the present invention, it is possible to prevent the property of the transistor element from being deteriorated, and the performance thereof can be improved.
The above object of the present invention can be also achieved by a first method of manufacturing an SOI substrate, provided with the processes of: forming a silicon nitride film or silicon nitride oxide film on a surface of either one of a single crystal silicon substrate and a support substrate; forming a silicon oxide film on a surface of the formed silicon nitride film or silicon nitride oxide film; laminating the single crystal silicon substrate and the support substrate onto each other by using a surface of the silicon oxide film as a lamination plane; and reducing a film thickness of the single crystal silicon substrate laminated on the support substrate.
According to the first method of manufacturing the SOI substrate, it is possible to manufacture the above described SOI substrate of the present invention. In particular, it is possible to form the silicon nitride film or silicon nitride oxide film on the surface of either one of the single crystal silicon substrate and the support substrate, and it is further possible, after forming the silicon oxide film on the surface thereof, by laminating the single crystal silicon substrate and the support substrate with the surface of the silicon oxide film as the lamination plane, to improve the laminating or bonding property between the single crystal silicon substrate and the support substrate. Therefore, the lamination or bonding strength between the support substrate and the single crystal silicon substrate becomes high and the reliability thereof can be improved. Further, the impurities contained in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate can be prevented from being diffused toward the single crystal silicon layer.
In addition, in the first method of manufacturing the SOI substrate, it is desirable to form the silicon nitride film or silicon nitride oxide film on the surface of the single crystal silicon substrate. By manufacturing in this manner, since it is possible to position the silicon nitride film or silicon nitride oxide film at a side closer to the single crystal silicon layer than the lamination plane between the support substrate and the single crystal silicon substrate after the lamination, it is possible to prevent not only the impurities contained in the support substrate but also the impurities absorbed on the lamination plane from being diffused toward the single crystal silicon layer.
The above object of the present invention can be also achieved by a second method of manufacturing an SOI substrate, provided with the processes of: forming a silicon oxide film on a surface of a single crystal silicon substrate; forming a silicon nitride film or silicon nitride oxide film below the silicon oxide film at a side thereof facing to the single crystal silicon substrate; laminating the single crystal silicon substrate and a support substrate onto each other by using a surface of the silicon oxide film as a lamination plane; and reducing a film thickness of the single crystal silicon substrate laminated on the support substrate.
According to the second method of manufacturing the SOI substrate, it is possible to manufacture the above described SOI substrate of the present invention. In particular, after forming the oxide film on the single crystal silicon substrate, by forming the silicon nitride film or silicon nitride oxide film on the surface of the single crystal silicon substrate through this oxide film, and then by laminating the single crystal silicon substrate and the support substrate with the surface of the silicon oxide film as the lamination plane, it is possible to improve the lamination or bonding property between the single crystal silicon substrate and the support substrate. Therefore, the lamination or bonding strength between the support substrate and the single crystal silicon substrate can be improved, and the reliability thereof can be improved. Further, it is possible to prevent the impurities included in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate from being diffused toward the single crystal silicon layer.
In addition, in the second method of manufacturing the SOI substrate, because the silicon nitride film or silicon nitride oxide film is formed on the surface of the single crystal silicon substrate, since it is possible to position the silicon nitride film or silicon nitride oxide film at a side closer to the single crystal silicon layer than the lamination plane between the support substrate and the single crystal silicon substrate after the lamination, it is possible to prevent not only the impurities contained in the support substrate but also the impurities absorbed on the lamination plane from being diffused toward the single crystal silicon layer.
In one aspect of the second method of the present invention, in the process of forming the silicon oxide film, the oxide silicon film is formed by thermally oxidizing the surface of the single crystal silicon substrate, and in the process of forming the silicon nitride film or silicon nitride oxide film, the silicon nitride film or silicon nitride oxide film is formed between the silicon oxide film and the single crystal silicon substrate by nitriding or oxynitriding the surface of the single crystal silicon substrate formed with the silicon oxide film under dinitrogen monoxide or nitric monoxide atmosphere.
According to this aspect, although the silicon nitride film or silicon nitride oxide film and the silicon oxide film may be formed by using the CVD method on the surface of the single crystal silicon substrate or the support substrate, the manufacturing processes can be simplified by using the thermal oxidizing method on the surface of the single crystal silicon substrate. Further, the silicon nitride film or silicon nitride oxide film and the silicon oxide film having the uniform thickness and being smoothed can be formed. Furthermore, it is possible to improve the adherence between the single crystal silicon substrate and the silicon nitride film or silicon nitride oxide film.
The above object of the present invention can be also achieved by a third method of manufacturing an SOI substrate, provided with the processes of: forming a first silicon oxide film on a surface of either one of a single crystal silicon substrate and a support substrate; forming a silicon nitride film or silicon nitride oxide film on a surface of the first silicon oxide film; forming a second silicon oxide film on a surface of the silicon nitride film or silicon nitride oxide film; laminating the single crystal silicon substrate and the support substrate onto each other by using a surface of the second silicon oxide film as a lamination plane; and reducing a film thickness of the single crystal silicon substrate laminated on the support substrate.
According to the third method of manufacturing the SOI substrate, it is possible to manufacture the above described SOI substrate of the present invention. In particular, the first silicon oxide film, the silicon nitride film or silicon nitride oxide film and the second silicon oxide film are sequentially formed on the surface of either one of the single crystal silicon substrate and the support substrate, and then the single crystal silicon substrate and the support substrate are laminated onto each other with the surface of the second silicon oxide film as the lamination plane, to thereby improve the adherence between the single crystal silicon substrate and the support substrate. Therefore, the lamination or bonding strength between the support substrate and the single crystal silicon substrate becomes high and the reliability thereof can be improved. Further, the impurities contained in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate can be prevented from being diffused toward the single crystal silicon layer.
In addition, in the third method of manufacturing the SOI substrate, it is desirable to form the silicon nitride film or silicon nitride oxide film on the surface of the single crystal silicon substrate. By manufacturing in this manner, since it is possible to position the silicon nitride film or silicon nitride oxide film at a side closer to the single crystal silicon layer than the lamination plane between the support substrate and the single crystal silicon substrate after the lamination, it is possible to prevent not only the impurities contained in the support substrate but also the impurities absorbed on the lamination plane from being diffused toward the single crystal silicon layer.
The above object of the present invention can be also achieved by a forth method of manufacturing an SOI substrate, provided with the processes of: forming a first silicon oxide film on a surface of a single crystal silicon substrate; forming a silicon nitride film or silicon nitride oxide film below the first silicon oxide film at a side thereof facing to the single crystal silicon substrate; forming a second silicon oxide film below the silicon nitride film or silicon nitride oxide film at a side thereof facing to the single crystal silicon substrate; laminating the single crystal silicon substrate and a support substrate onto each other by using a surface of the first silicon oxide film as a lamination plane; and reducing a film thickness of the single crystal silicon substrate laminated on the support substrate.
According to the forth method of manufacturing the SOI substrate, it is possible to manufacture the above described SOI substrate of the present invention. In particular, after forming the first oxide film on the surface of the single crystal silicon substrate, by forming the silicon nitride film or silicon nitride oxide film on the surface of the single crystal silicon substrate through this first oxide film, by forming the second silicon oxide film through this, and then by laminating the single crystal silicon substrate and the support substrate with the surface of the first silicon oxide film as the lamination plane, it is possible to improve the lamination or bonding property between the single crystal silicon substrate and the support substrate. Therefore, the lamination or bonding strength between the support substrate and the single crystal silicon substrate can be improved, and the reliability thereof can be improved. Further, it is possible to prevent the impurities included in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate from being diffused toward the single crystal silicon layer.
In addition, in the forth method of manufacturing the SOI substrate, because the silicon nitride film or silicon nitride oxide film is formed on the surface of the single crystal silicon substrate, since it is possible to position the silicon nitride film or silicon nitride oxide film at a side closer to the single crystal silicon layer than the lamination plane between the support substrate and the single crystal silicon substrate after the lamination, it is possible to prevent not only the impurities contained in the support substrate but also the impurities absorbed on the lamination plane from being diffused toward the single crystal silicon layer.
In one aspect of the forth method of the present invention, in the process of forming the first silicon oxide film, the first oxide silicon film is formed by thermally oxidizing the surface of the single crystal silicon substrate, in the process of forming the silicon nitride film or silicon nitride oxide film, the silicon nitride film or silicon nitride oxide film is formed by nitriding or oxynitriding the surface of the single crystal silicon substrate formed with the first silicon oxide film under dinitrogen monoxide or nitric monoxide atmosphere, and in the process of forming the second silicon oxide film, the second oxide silicon film is formed by thermally oxidizing the surface of the single crystal silicon substrate formed with the silicon nitride film or silicon nitride oxide film.
According to this aspect, the manufacturing processes can be simplified, and also the silicon nitride film or silicon nitride oxide film and the silicon oxide film having the uniform thickness and being smoothed can be formed. Furthermore, it is possible to improve the adherence between the single crystal silicon substrate and the silicon nitride film or silicon nitride oxide film.
In another aspect of the second method of the present invention, the method is further provided with the processes of: forming a light shield film on a surface of the support substrate; forming a second silicon oxide film on the surface of the support substrate including the light shield film; and smoothing a surface of the second silicon oxide film.
According to this aspect, it is possible to manufacture the above described SOI substrate of the present invention in its aspect that the light shield film is disposed.
In another aspect of the forth method of the present invention, the method is further provided with the processes of: forming a light shield film on a surface of the support substrate; forming a third silicon oxide film on the surface of the support substrate including the light shield film; and smoothing a surface of the third silicon oxide film.
According to this aspect, by smoothing the surface of the third silicon oxide film, it is possible to prevent the voids from being generated at the lamination plane between the support substrate and the single crystal silicon substrate. Accordingly, it is possible to improve the lamination strength. Further, since the silicon nitride film or silicon nitride oxide film has an effect to releases the stress at the lamination, it is possible to prevent the stripping off of the film or the like from being generated in case of forming the transistor element by using the SOI substrate, to thereby improve the yield of the product.
The above object of the present invention can be also achieved by a method of manufacturing an element substrate provided with the process of forming a semiconductor layer constituting a transistor element by using the single crystal silicon layer, by using the SOI substrate manufacture by any one of the above described first to forth methods of manufacturing the SOI substrate.
According to the method of manufacturing the element substrate, it is possible to manufacture the above described element substrate of the present invention.
The above object of the present invention can be also achieved by a second electro-optical apparatus provided with: a support substrate; a pixel electrode disposed above the support substrate; a transistor element disposed above the support substrate, connected to the pixel electrode and comprising a semiconductor layer including a channel region; a wiring disposed on the support substrate and connected to the transistor element; a light shield film disposed on the support substrate for covering at least the channel region from a side of the support substrate; and an insulation portion disposed at at least one of an interlayer space between the light shield film and the semiconductor layer and an interlayer space between the support substrate and the light shield film, and including a silicon nitride film or silicon nitride oxide film.
According to the second electro-optical apparatus of the present invention, by supplying a scanning signal, a video signal or the like to the wiring, it is possible for the transistor element to switch-control the pixel electrode, to thereby execute the active matrix driving operation. During such an operation, if the aforementioned return light is inputted to the channel region of the semiconductor, layer constituting the transistor element, the transistor characteristic is changed due to the generation of the light leak current. In fact, according to the present invention, since the light shield film is disposed at the bottom side of the channel region at least in the image display region or the light input region of the semiconductor layer (i.e., the region where the input light related to the image display is reflected or transmitted, other than the peripheral region or the like on the support substrate), it is possible to effectively prevent the generation of the light leak current due to the return light.
Further, according to the present invention, the insulation portion is disposed at at least one of the interlayer space between the light shield film and the semiconductor layer and the interlayer space between the support substrate and the light shield film, which includes the silicon nitride film or silicon nitride oxide film. This silicon nitride film or silicon nitride oxide film can be formed as a dense or compact film, as compared with the silicon oxide film which is the typical example of the inter-layer insulation film formed in the lamination structure on the support substrate and other various insulation films, various conductive films, various semiconductor films and so forth constituting the lamination structure on the support substrate. Thus, it is possible to drastically decrease the transmission rate of the oxidizers such as oxygen, moisture and the like. Namely, since the oxidizers such as oxygen, moisture and the like can hardly pass through the dense silicon nitride film or silicon nitride oxide film, it can hardly reach the light shield film. Accordingly, even if the oxidizers such as oxygen, moisture and the like enter during the operation or the production of the second electro-optical apparatus, from the boundary face in the lamination structure which is constructed on the support substrate, or from the side of the surface on which the transistor element or the like is formed on the support substrate, or even if the oxidizers are taken into various conductive films, various insulation films, various semiconductor films and so forth formed on the support substrate, during the production thereof, it is possible to reduce the amount of the oxidizers, which are reachable to the light shield film during the operation or the production of the second electro-optical apparatus, among the total oxidizers, by virtue of the dense silicon nitride film or silicon nitride oxide film. Thus, during the operation or the production of the second electro-optical apparatus, it is possible to effectively prevent the light shield film from being oxidized. Therefore, it is possible to prevent the increase in the light transmission rate of the light shield film caused by the oxidization thereof, namely, it is possible to effectively prevent the drop in the light shield function thereof. Consequently, it is possible to maintain the high performance of the transistor element.
Especially, in case of employing such a structure that the insulation portion including the dense silicon nitride film or silicon nitride oxide film is disposed between the light shield film and the semiconductor layer, it is also possible to effectively avoid the contamination that the impurities are diffused into the semiconductor layer from the light shield film comprising the high melting point, or the like. Namely, the impurities from the light shield film can hardly pass through the dense silicon nitride film or silicon nitride oxide film of the insulation portion, they can hardly reach the semiconductor layer. Therefore, it is possible to avoid the degradation in the performance of the transistor element due to the contamination of the semiconductor layer from the light shield layer.
As a result, according to the second electro-optical apparatus of the present invention, finally, it is possible to perform a high quality image display for a long period of time.
In addition, in case of constituting the second electro-optical apparatus as the light transparent type, a light transparent substrate may be used as the support substrate.
In one aspect of the second electro-optical apparatus of the present invention, the insulation portion has a multiple-layered structure.
According to this aspect, as the insulation portion including the dense silicon nitride film or silicon nitride oxide film is formed to have the multiple-layered structure, the capability of shielding the oxidizers such as oxygen, moisture and the like at the insulation portion can be improved. Therefore, it is possible to more effectively avoid the oxidizing of the light shield film and the contamination due to the light shield film.
In this aspect, the multiple-layered structure may include: the silicon nitride film or silicon nitride oxide film; and a silicon oxide film formed on an upper surface or bottom surface of the silicon nitride film or silicon nitride oxide film.
By constructing in this manner, it is possible to even more improve the capability of shielding the oxidizers at the insulation portion by virtue of the lamination structure of the silicon nitride film or silicon nitride oxide film and the silicon oxide film formed on this. Further, for example, it is possible to employ a lamination structure by using three or more films, e.g., such a lamination structure that two of the silicon nitride film or silicon nitride oxide film sandwich the silicon oxide film, such a lamination structure that two silicon oxide films sandwich the silicon nitride film or silicon nitride oxide film, and so on.
Incidentally, it is possible to employ a single layer structure, e.g. such a structure that the insulation portion consists of only the silicon nitride film or only the silicon nitride oxide.
In another aspect of the second electro-optical apparatus of the present invention, the insulation portion is adhered to the light shield film.
According to this aspect, since the insulation portion including the dense silicon nitride film or silicon nitride oxide film is adhered to the upper surface, the bottom surface, the both surfaces, the end, or the edge of the light shield film, it is possible to reduce the possibility that the oxidizers such as oxygen, moisture and the like included in the other inter-layer insulation films etc., reach the light shield film.
In another aspect of the second electro-optical apparatus of the present invention, the insulation portion is opposed to the light shield film through an inter-layer insulation film.
According to this aspect, the insulation portion including the dense silicon nitride film or silicon nitride oxide film is opposed to the light shield film through the inter-layer insulation film such as a silicon oxide film or the like, it is possible to shield the oxidizers in some degrees at a position apart from the light shield film.
In another aspect of the second electro-optical apparatus of the present invention, the light shield film has a plane pattern in a predetermined shape, and the insulation portion has a plane pattern in such a shape that the insulation portion completely covers the light shield film and an edge of the insulation portion is apart from an edge of the light shield film.
According to this aspect, it is possible to shield the light for at least the channel region of the semiconductor layer from the bottom side thereof, by the light shield layer having the plane pattern in the predetermined shape such as a lattice or grid like shape, a stripe shape, an island-like shape or the like. The insulation portion has the plane pattern in the shape for completely covering the light shield film such as a lattice or grid like shape, a stripe shape, an island-like shape or the like, which is slightly or by one round larger than the light shield film, and the edge of the insulation portion is apart from the edge of the light shield film when viewing it on the plane of the support substrate. Therefore, it is possible for the insulation portion to cover the light shield film three-dimensionally from the upper side, the bottom side or the both sides, on the support substrate, so that it is possible to further reduce the possibility that the oxidizers such as oxygen, moisture and the like reach the light shield film.
Incidentally, the insulation portion may be formed substantially all over the surface of the support substrate, regardless of the plane pattern of the light shield film. Also, even if the light shield is not completely covered, the similar effect can be obtained to some extents.
In another aspect of the second electro-optical apparatus of the present invention, the semiconductor layer has an SOI structure comprising a single crystal silicon film.
According to this aspect, by virtue of the SOI technique, it is possible to construct the transistor element such as a MOSFET for high-performance-driving, a TFT for pixel-switching or the like which is superior in the transistor characteristic such as a high speed, a low electric-power-consumption, a higher integration and the like, on the support substrate, by using the single crystal silicon film superior in the crystallization.
In another aspect of the second electro-optical apparatus of the present invention, the semiconductor comprises a poly-silicon film or amorphous silicon film.
According to this aspect, by virtue of the semiconductor layer comprising the poly-silicon film or the amorphous silicon film on the support substrate such as the glass substrate, the quartz substrate or the like, the transistor element can be manufactured at a relatively low cost.
In another aspect of the second electro-optical apparatus of the present invention, the light shield film comprises a metal of high melting point.
According to this aspect, the light shield film comprises a film including a metal of high temperature point, such as a simple substance of a metal, an alloy, a metallic silicide, a poly-silicide, a lamination body in which some of them are laminated or the like, which includes at least one of high melting point metals, for example, such as Ti (Titanium), Cr (chromium), W (Tungsten), Ta (Tantlum), Mo (Molybdenum), Pd (palladium) and the like. Accordingly, it is possible to obtain the high light-shielding capability by the light shield film.
In addition, the light shield film may comprise a silicon film, which performs light-shielding by partially absorbing the light.
In another aspect of the second electro-optical apparatus of the present invention, a total layer thickness of the silicon nitride film or silicon nitride oxide film of the insulation portion is not greater than 100 nm.
According to this aspect, since the total thickness of the silicon nitride film or silicon nitride oxide film having a light absorption property dependent on the frequency of the light is not greater than 100 nm, even if such a structure is adopted that the display light passes through the insulation portion, still it is possible to reduce the coloring of the display light due to the light absorption at the insulation portion. For example, if the display light passes through the silicon nitride film or silicon nitride oxide film whose film thickness is greater than 100 nm, it is observed that the display light becomes more or less yellowish. However, by limiting the total thickness of the silicon nitride film or silicon nitride oxide film to be not greater than 100 nm, the phenomena that the display light becomes yellowish can be certainly reduced.
In another aspect of the second electro-optical apparatus of the present invention, the second electro-optical apparatus is further provided with: an opposite substrate opposed to the support substrate; and an electro-optical material layer interposed between the support substrate and the opposite substrate.
According to this aspect, the electro-optical apparatus such as a liquid crystal device or the like, in which the electro-optical material layer e.g., a liquid crystal layer is disposed between the pair of the support substrate and the opposite substrate, can be constructed. In particular, since the apparatus is provided with the above described light shield film and the insulation portion, the excellent light shielding property can be maintained, and the high quality image display can be performed for a long period of time.
In another aspect of the second electro-optical apparatus of the present invention, an edge of the insulation portion includes an area within 2 xcexcm from an edge of the light shield film.
According to this aspect, it is possible to reduce the possibility that the oxidizers such as oxygen, moisture and the like reach the light shield film from the edge of the insulation portion and at the same time possible to drastically reduce the decrease rate of the display light at the insulation portion.
In another aspect of the second electro-optical apparatus of the present invention, an edge of the insulation portion is self-aligned with an edge of the light shield film.
According to this aspect, it is possible to reduce the decrease rate of the display light at the insulation portion to almost its limit.
The above object of the present invention can be achieved by a second electronic equipment provided with the above described second electro-optical apparatus (including various aspects thereof).
According to the second electronic equipment of the present invention, since it is provided with the above described second electro-optical apparatus of the present invention, it is possible to realize various electronic equipments capable of performing the bright and high quality image display for a long period of time, such as a projection type display apparatus, an liquid crystal television set, a portable telephone, an electronic memo, a word processor, a view finder type or a monitor direct view type of a video tape recorder, a work station, a television telephone, a POS terminal, a touch panel, and so on.
The above object of the present invention can be also achieved by a first method of manufacturing an electro-optical apparatus provided with the processes of: forming a light shield film in a predetermined area on a support substrate; forming an insulation portion including a silicon nitride film or silicon nitride oxide film on the slight shield film directly or through an inter-layer insulation film; forming a semiconductor layer on the insulation portion directly or thorough an inter-layer insulation film; forming a transistor element, whose channel region is disposed in an area covered by the light shield film from a bottom side thereof with using the semiconductor layer as a constitutional element; and forming a wiring and a pixel electrode connected to the transistor element.
According to the first method of manufacturing the electro-optical apparatus of the present invention, at first, the light shield film is formed in the predetermined area (e.g., a grid-like shaped, stripe-shaped or island-like-shaped area) on the support substrate such as a glass substrate, a silicon substrate, a quartz substrate or the like. Here, for example, such a light shield film is formed as a light shield film is firstly formed all over one surface by sputtering a metal of high melting point and is then patterned by the photo-lithography and etching processes. Then, on this light shield film directly or through the inter-layer insulation film such as a silicon oxide film, the insulation portion including the silicon nitride film or silicon nitride oxide film is formed. Here, for example, by firstly forming the silicon oxide film and then nitriding or oxynitriding its surface under dinitrogen monoxide or nitric monoxide atmosphere, or by the CVD method, the silicon nitride film or the silicon nitride oxide film may be formed. Further on this, the semiconductor layer such as a poly-silicon film, an amorphous silicon film, a single crystal silicon film or the like is formed directly or thorough an inter-layer insulation film. Then, the transistor element such as a TFT is formed, whose channel region constituted by the semiconductor layer is disposed in the area covered by the light shield film from the bottom side thereof as the semiconductor layer, at least in the light input region or the image display region. Then, the wiring connected with this transistor element is formed from a conductive metal film or poly-silicon film or the like, while the pixel electrode is formed from the ITO (Indium Tin Oxide) film or the like. Therefore, the second electro-optical apparatus of the present invention in the aspect having at least the above described insulation portion on the upper side of the light shield film can be manufactured relatively easily
In one aspect of the first method of manufacturing the electro-optical apparatus of the present invention, the method is further provided with the process of forming another insulation portion including a silicon nitride film or silicon nitride oxide film above the support substrate, before the process of forming the light shield film.
According to this aspect, before the formation of the light shield film, another insulation portion including the silicon nitride film or silicon nitride oxide film is formed on the support substrate. Thus, it is possible to relatively easily manufacture the above described second electro-optical apparatus of the present invention in the aspect having the structure that the two insulation portions sandwich the light shield film.
The above object of the present invention can be also achieved by a second method of manufacturing an electro-optical apparatus provided with the processes of: forming an insulation portion including a silicon nitride film or silicon nitride oxide film on a support substrate; forming a light shield film in a predetermined area on a support substrate directly or through an inter-layer insulation film; forming a semiconductor layer on the light shield film directly or thorough an inter-layer insulation; forming a transistor element, whose channel region is disposed in an area covered by the light shield film from a bottom side thereof with using the semiconductor layer as a constitutional element; and forming a wiring and a pixel electrode connected to the transistor element.
According to the second method of manufacturing the electro-optical apparatus of the present invention, at first, the insulation portion including the silicon nitride film or silicon nitride oxide film is formed on a support substrate such as a glass substrate, a silicon substrate, a quartz substrate or the like. Here, for example, by firstly forming the silicon oxide film and then nitriding or oxynitriding its surface under dinitrogen monoxide or nitric monoxide atmosphere, or by the CVD method, the silicon nitride film or the silicon nitride oxide film may be formed. Then, the light shield film is formed in the predetermined area (e.g., a grid-like shaped, stripe-shaped or island-like-shaped area) on this insulation portion. Here, for example, such a light shield film is formed as a light shield film is firstly formed all over one surface by sputtering a metal of high melting point and is then patterned by the photo-lithography and etching processes. Then, on this light shield film directly or through the inter-layer insulation film, the semiconductor layer such as a poly-silicon film, an amorphous silicon film, a single crystal silicon film or the like is formed directly or thorough an inter-layer insulation film. Then, the transistor element such as a TFT is formed, whose channel region constituted by the semiconductor layer is disposed in the area covered by the light shield film from the bottom side thereof as the semiconductor layer, at least in the light input region or the image display region. Then, the wiring connected with this transistor element is formed from a conductive metal film or poly-silicon film or the like, while the pixel electrode is formed from the ITO (Indium Tin Oxide) film or the like. Therefore, the second electro-optical apparatus of the present invention in the aspect having the insulation portion is disposed below the light shield film can be manufactured relatively easily
In one aspect of the first or second method of manufacturing the electro-optical apparatus of the present invention, the process of forming the semiconductor layer is provided with the processes of: laminating (i) a single crystal silicon substrate on which the semiconductor layer is formed and (ii) the support substrate on which the light shield layer and the insulation portion are formed, onto each other, and reducing a film thickness of the single crystal silicon substrate after being laminated onto the support substrate.
According to this aspect, at first, the semiconductor layer is formed on the single crystal silicon substrate. Then, this single crystal silicon substrate and the support substrate, on which the light shield film and the insulation film have been already formed, are laminated onto each other. Here, for example, after the silicon oxide film is formed on the lamination plane and this lamination plane is smoothed, both of the substrates are adhered to each other by using the hydrogen coupling force, so that both of the substrates are laminated. Further, by the heating process, the lamination strength is upgraded. Successively, the thickness of the single crystal silicon substrate is reduced. Here, by leaving the semiconductor layer on the support substrate and stripping off the single crystal silicon substrate from the support substrate, the thickness of the single crystal silicon substrate may be reduced. Alternatively, the thickness of the single crystal silicon substrate may be reduced by etching, polishing, cutting or the like with respect to the single crystal silicon substrate. Therefore, the second electro-optical apparatus in the aspect having the extremely high performance transistor element with the single crystal silicon film on the SOI substrate as the semiconductor element can be relatively easily manufactured.
The above object of the present invention can be also achieved by a semiconductor device including a transistor element and the above described SOI substrate of the present invention, the transistor element including (i) a semiconductor layer comprising the single crystal silicon layer and (ii) an electrically conductive member disposed at one side of the insulation portion facing to the support substrate.
According to the semiconductor device of the present invention, it is possible to almost perfectly prevent the impurities contained in the support substrate and the impurities absorbed on the lamination plane between the support substrate and the single crystal silicon substrate from being diffused toward the transistor element, by virtue of the insulation portion. Thus, it is possible to effectively prevent the performance of the transistor element from being deteriorated. Further, it is possible to utilize the electrically conductive member formed on one side of the insulation portion facing to the support substrate, as a light shielding film, a gate electrode or gate line or the like for example, while the diffusion of the impurities from this electrically conductive member toward the transistor element can be effectively prevented by the insulation portion.
In one aspect of the semiconductor device of the present invention, one portion of the electrically conductive member functions as a gate electrode or gate line of the transistor element.
According to this aspect, such a transistor element that the gate electrode or gate line is formed on the support substrate and that, further above it, the semiconductor layer is disposed through the insulation portion, which functions as the gate insulation film, can be obtained. Incidentally, by forming the gate electrode or gate line from a light shielding film, the gate electrode or gate line may additionally have the function of the light shielding film.
The above object of the present invention can be also achieved by a third electronic equipment having the above described semiconductor device of the present invention (including various aspects thereof).
According to the third electronic equipment of the present invention, since it has the above described semiconductor device of the present invention, various electronic equipments including the high performance transistor elements can be realized.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings briefly described below.